Lamp socket



A. G. STEINMAYER LAMP SOCKET Filed Dec. 28, 1929 Patented Aug. 23, 1932UNITED STATES (PATENT OFFICE ALWIN G. STEINMAYEB, OEMILWAUKEE, Wisconsn, 'AssIGNon'ro niNnMAmIAL COMPANY, or seen: MILWAUKEE, WISCONSIN, ACORPORATION or WISCONSIN LAMP socxnr Application filed December 28,1929. Serial No. 417,111.

r This invention relates to certain new and useful improvements in lampsockets and refers more particularly to street lighting fixture socketsof the series type.

} Sockets of this character usually have upwardly extending adjacentcontact arms or bayonets, by which they are connected with theirreceptacles, to electrically connecttheir lamps with the line, andheretofore it has been customary to insert a thin film of insulatingmaterial between the bayonets to normally maintain them insulated fromeach other, the film puncturing upon failure of the lamp, to permitthe'bayonets to be electrically connected and thus maintain thecontinuity of the circuit.

This method of'i'nsurin'g continuity of a series circuit, while itserved its purpose,was

objectionable in that different thicknesses and types of film wererequired for different circuits, and with this and other objectionsmind, this invention contemplates as oneof its objects the provision of'novel'means for insuring the continuity of a series circuit uponfailure of a lamp which obviates the necessity of an insulating film. iv c I Another object of this invention resides in the provision of asocket of the character described having means for insuring thecontinuity of the circuit upon failure of its lamp, which is notdestroyed in operation and may be used again after being cleaned.

Another object of this inve'ntionresides in the provision of a readilyremovable cut-out unit for insuring continuity of a seriescircuit uponfailure of a lamp whereby the same may be applied to sockets Without inany way altering their design orconstruction by merely substituting itfor the usual film.

A further object of this invention resides in the provision of a socketof the character described having means for insuring ,the continuity ofthe circuit upon failure of its lamp which means may, be readilyadjusted to function at different voltages.

And a more specific object resides in the provision of a socket of thecharacter described having a readilyqremovable cut-out unit insertablebetween its bayonet arms and which is provided with an air gapfac'rosswhich the current jumps upon failure of the lamp, to fuse the metalof-the members forming the gap to thus maintain the continuity of thecircuit.

With the above and other objects in view. which will appear as thedescription proceeds, my invention resides in the novel construction,combination and'arrangement of parts substantially as hereinafterdescribed and more particularly defined by the appended claims, it beingunderstood that such changes in: the, precise embodiment of thehereindisclosed invention may be madeas come within the scope of theclaims.

. In the accompanying drawing, I have illustrated one completeexampleiof the physical embodiment of my invention constructedaccordingto the best mode I have so far deprinciples thereof, and inwhich: 7

Figure 1 is an elevational view of a conventional series type streetlighting socket illustrated in its position of mounting within areceptacle and provided with the device of this invention, parts thereofbeing broken away and in section to illustrate structural details; and

Figure 2 is'a fragmentary perspective view of the outer ends of thesocket bayonet arms and the cut-out unit which is insertabletherebetween.

Referring now more particularly to the accompanying drawing, the numeral5 represents the body of a series type street lighting socket which isformed ofinsulating material and is adapted'to receive anincandes- Tcent lamp 6- a portion of which is illustrated.

Inasmuch as the internal construction of the socket is of conventionaldesign and forms no part of this invention it has not been shown indetail and the description will be directed to only'those elementsentering directly into the combination.

As is customary in sockets of this type, a pair of bayonet arms 7 and 8extend upwardly therefrom, one of which is connected with the outerterminal or shell of the socket by means, not shown, and the other withthe central terminal.

To maintain the continuity of thecircuit 1 vised for the practicalapplication ofthe whenever the lamp 6 is removed the socket is soconstructed that the outer shell and the center contact are electricallyconnected by the removal of the lamp and are disconnected by theinsertion thereof to permit the lamp to be connected with a line. Toeffect this connection conductors 9 and 10 leading from the line areconnected with terminals 11 and 12 of the socket receptacle, and withwhich the bayonet arms engage in the customary 11121111191.

The bayonet arms 7 and S are formed of resilient spring metal todetachably maintain the socket engaged in its receptacle withits bayonetarms in electrical engagement with the receptacleterminals 11 and 12.

The resilience of the bayonet arms also tends to electrically connecttheir outer ends,

and to maintain the same out ofcontact it has heretofore been customaryto insert a piece of film therebetween. The film was relatively thin andformed of material which punctured at voltages of approximately300 to400 volts to which the current builds up upon failure of the lamp. Inthis manner continuity of the circuit was maintained after failure ofthe lan1p,'but'the necessity of replacing the punctured film and thefact that different thicknesses and sizes of film were required fordifferent circuits, made this method objectionable.

The present invention eliminates the objectionable insulating film byproviding a novel I cut-out device, indicated generally by the numeral13, and which is readily removably insertable between the bayonet arms7and 8. The device has a body of insulating material whose upper end 15is of reduced thickness and whose medial portion tapers outwardly toprovide a relatively heavy lower portion.

Secured to'the body of insulating material 14 are two spring lingers 16and 17 the outer ends of which are shaped to conform to the'[LCljflCEHtouter ends of the bayonet arms'l and 8 to bereceivedtherebetween and maintain the unit in its proper position. The 'finger16 extends to the bottom of the block of insulating material and thefinger 17 terminates at a point spaced from the bottomzthereof for apurpose to be later described.

Also carried by the body of insulating material is a. pair of L shapedmembers 18 and 19 mounted directly adjacent and in electrical engagementwith the fingers 16 and 17 respectively. The member 18 is shorter thanthe member 19 and with the finger 16 whose inner portion is disposedbetween it and the insulating material, is rigidly connected with theinsulating material by rivets 20. The other L shaped member 19 and thefinger l7 overlap at only their adjacent end portions and are connectedwith the body of insulatin; material by screws 21.

The horizontal arms 22 and 23 of the members '18 and 19, respectively,are directed toward each other, but are spaced to provide an air gap,one of the members preferably having its end V shaped to form a knifeedge so that accurate adjustment of the gap is facilitated. Adjustmentof the gap is afforded by means of screws 24 which pass throughcounterbored apertures in the insulating body member and are threaded inthe lower portion of the member 19 to draw the same inwardly toward themember 18, this movement of the lower end of the member 19 beingaccommodated by the space provided between the member 19 and theadjacent side of the insulating body beneath the finger 17.

It is noted that the apertures in the insulating body through which therivets 20 and the screws 21 and 2t pass are counterbored so that theheads thereof are disposed within the insulating material to precludethe possibility of short cireuiting the members 18 and 19 andconsequently the bayonet arms 7 and 8. Vith the gap between the members18 and 19 properly adjusted the unit is insertedbetween the bayonetarms, as illustrated in Figure 1, and upon failure of the lamp thecurrent quickly builds up to a point at which it jumps across the gapand slightly fuses the edges thereof to maintain the continuity of thecircuit.

When tne operator replaces the lamp he removes the unit from the socketand with a thin lile cleans out the beads ofmetal'which have bridged thegap and re-adjusts its width if necessarv. One end of the file may beprovided with "a feeler or thickness gauge to as-.

sist in adjusting the gap. The unit is then in condition for furtheroperation and may be replaced between the bayonet arms of the socket.

From the foregoing description, taken in connection with theaccompanying drawing, it will be readily apparent to those skilled inthe art to which an invention of the character described appertains,that I provide novel means for insuring the continuity ofcircuit in astreet series lighting socket which obviates the-necessity of the usualfilm of insulating material and which. by beingreadily removable andinsertable between the bayonet arms of the-socket, may be used withsockets without in any way altering their de' sign or construction.

What I claim as my invention is:

1. An electric cut-out unit readily insertable between the bayonet armsof a series type lamp socket to maintain the same eleced beyond theblock of insulating material and spaced slightly from each other to forman air gap across which curren'tmay jump .to fusesaid portions.

2. An electric cut-out unit readily insertable between the bayonet armsofa series type light socket to normally insulate the same from eachother and electrically connect the same upon failure of a lamp securedin the socket, comprising an insulating member conforming substantiallyto the size and shape of the socket member bayonet arms, contact memberscarried by the block of insulating material and directly engageable withthe bayonet arms, said contact members having portions extended beyondone end of the insulating member and slightly spaced from each other toform an air gap, and means for adjusting the width of said air g Anelectric cut-out unit adapted to be mounted between the bayonet arms ofa series type light socket to normally insulate the same from each otherand electrically connect the same upon failure of a lamp secured in thesocket, comprising a body of insulating material, spring terminalmembers on opposite sides of the body of insulating material and shapedto conform to the shape of the bayonet arms for snug engagementtherewith, and contact members carried by the body of insulatingmaterial, said contact members being electrically connected with thespring terminal members and having portions projected beyond one end ofthe body of insulating material and spaced slightly from each other toform an air gap across which current flowing to the lamp jumps uponfailure of the lamp.

4. An electric cut-out unit of the character described comprising a bodyof insulating material having substantially fiat sides, a contactmemberfixed to one side of the body with a portion extended beyond oneend thereof, a second contact member, means for securing one end portionof the second contact member to the body, its other end portion beingextended beyond said end of the body and directed toward the firstmentioned contact member but spaced therefrom to provide an air gap,means whereby the second contact member is spaced from the adjacent sideof the body throughout its major portion to permit the same to be movedtoward the first mentioned contact member to adjust the width of thegap, and means connecting the body with said spaced portion of thecontact member to draw the same toward the body of insulating material.

5. An electric cut-out unit for use with a series type light socket,comprising a block of insulating material, terminal members carried bythe block of insulating material with adjacent ends projected beyond theblock of insulating materialand spaced from each other to form an airgap, the projected end of one of said terminal members being formed witha knife edge, and means for moving one of the members to adjust thewidth of the gap.

6. An electrical cut-out unit for use with a series type light socketcomprising an insulating member, a terminal member fixed to saidinsulating member, a second terminal member having one end portion fixedto the insulatingmember and its other end portion adjacent to but spacedfrom the insulating member and the first mentioned terminal member toprovide an air gap, and means connecting the free end of said secondmentioned terminal member with the insulating material and operable tomove said free end of the second mentioned terminal member toward theinsulating member to adjust the width of the air gap.

7. An electrical cut-out unit for use with a series type light socketcomprising an insulating member, a terminal member fixed to saidinsulating member, a second terminal member fixed to the insulatingmember at one end with its other free end portion spaced from theinsulating member and adjacent to but spaced from the first mentionedterminal member to provide an air ap, and means for moving the free endof sald second mentioned terminal member toward the insulating member toadjust the width of the air gap.

8. An electrical cut-out unit for use with a series type light socketcomprising an insulating member, contact fingers and terminal members,means securin one contact finger and terminal member rigidly to theinsulating member, the other contact finger and terminal memberoverlapping at their adjacent ends whereby the terminal member is spacedfrom the insulating member throughout its major portion, means securinthe over-lapping ends of the second mentioned contact finger andterminal member to the insulating member, the free end of the secondmentioned terminal member being adjacent to but spaced from the firstmentioned terminal member to provide an air gap, and means for drawingthe free end of the second mentioned terminal member toward theinsulating member to adjust the width of the air gap.

In testimony whereof I have hereunto affixed my signature.

ALWIN G. STEINMAYER.

